One billion people worldwide live in slums, a number that will likely double by 2030. The characteristics of slum life vary greatly between geographic regions, but they are generally inhabited by the very poor or socially disadvantaged. Slum buildings can be simple shacks or permanent and well-maintained structures but lack clean water, electricity, sanitation and other basic services. In this post, I've included images from several slums including Kibera slum in Nairobi, Kenya, the second largest slum in Africa (and the third largest in the world); New Building slum in central Malabo, Equatorial Guinea; Pinheirinho slum - where residents recently resisted police efforts to forcibly evict them; and slum dwellers from Kolkata, Mumbai and New Delhi, India. India has about 93 million slum dwellers and as much as 50% of New Delhi's population is thought to live in slums, 60% of Mumbai. -- Paula Nelson (55 photos total)Cambodian lawmaker Mu Sochuo, from the opposition Sam Rainsy party, pleads with riot policemen to stop a forced eviction of villagers at a slum village in the centre of Phnom Penh, Jan. 4, 2012. Cambodian lawmakers from the opposition Sam Rainsy party visited the village after authorities forcefully evicted villagers from the Borei Keila community in the capital. (Tang Chhin Sothy/AFP/Getty Images)